This invention relates generally to the field of micro-mechanical motors and more specifically to micro-machined linear stepper motors.
U.S. Pat. No. 5,483,387 issued to Bauhahn, et al and hereby incorporated by reference discloses a high pass optical filter. The high pass optical filter disclosed in the '387 patent utilizes a simple magnetic slider and a single electromagnetic stator to tune the high pass optical filter. The actuator however, is difficult to control and does not provide sufficient force or displacement.
A number of electric motors have been disclosed in the large scale form including rotary stepping motors. There is extensive literature on the design, performance and control of variable reluctance or switched reluctance stepping motors. Most of the literature relates to rotary steppers but the operating principles of linear steppers is the same. The operation can be understood and is described further in the description of the preferred embodiment utilizing FIGS. 7 and 8. Applicants invention incorporates a multi-pole variable reluctance linear stepping motor to improve the operation of the high pass optical filter disclosed in the '387. The stepping motor provides additional displacement and discrete displacement thereby improving the precision of the high pass filter.
For further reference, see Semi-Annual Technical Reports "LIGA-Based Tuneable Optical Filters for Multispectral IR Imagers and Gas Analyzers", by Ohnstein et al., submitted Feb. 2, 1996.